Unusual Upper Cretaceous Find N. Texas

[Ferg01]

We were walking searching a creek bed 20 miles or so north of Dallas and finding nice shell imprints and partial fossils (very common) in the exposed limestone here when my 10 year old niece said "Look at this!" It was about 6 inches above the uppermost limestone/chalk layer in dirt and 2/3 exposed on a steep face. It was 12-15 ft. below top soil.

I am new to all this and but haven't even seen anything remotely close. I'm guessing an ancient marine plant (judging by some smaller petrified shells/crustacians in the matrix and bark?) but it's a wild guess.

We've just got to know!!

PS- My apologies in advance for possible overkill on the photos and 3 posts to get them up with the 2 mg limit. But the almost symmetric concavity is seemed hard to convey with camera.

Also...thanking you all in advance and for helping a newbie!!

Warmest Regards,

John

[Ferg01]

To go with prior post.

[Fossildude19]

Possibly a Rudist?

More pictures HERE.

Someone here should know for sure.

Regards,

[Ferg01]

Last photo

[Fossildude19]

John,

You can add photos in the same thread by clicking on the "More Reply Options" button in the bottom right hand corner under the "Reply to this topic" box.

Then you should get the same ability to add photos.

Regards,

EDIT: It is preferable to keep the same item for ID in one thread, to avoid confusion.

[Ferg01]

Fossil Dude 19,

Thank you. Will do.

[doushantuo]

Fairly shouts "rudist" to me

Rudists formed bioherms("reefs",with mostly good hydrocarbon prospectivity,BTW) and are believed by some to have harboured symbionts,much like TRIDACNA.

http://dergipark.ulakbim.gov.tr/tbtkearth/article/view/5000024224/5000024461

Skelton/Gili(not peer reviewed):

https://www.researchgate.net/profile/Eulalia_Gili/publication/274457879_Palaeoecological_classification_of_rudist_morphotypes/links/552083750cf29dcabb0b5519.pdf/download?version=vrp

Edited June 9, 2016 by doushantuo

[Xiphactinus]

Yes, a rudist clam. Durania. You can see more about half way down this page.

http://oceansofkansas.com/FieldGuide1.html

[doushantuo]

somewhat murky:

http://www2.uibk.ac.at/downloads/c715/gpm_23/23_037-059.pdf

via BIOONE OR RG:

https://www.researchgate.net/profile/Robert_Scott4/publication/240776255_Albian_caprinid_rudists_from_Texas_re-evaluated/links/5658793608ae1ef9297dc5a7.pdf/download?version=vrp

good pix of structures:

(MASSE)

http://eprints.ucm.es/26710/1/1-s2.0-S019566710-01.pdf

Edited June 9, 2016 by doushantuo

[doushantuo]

this shows the morphology of Durania:

http://ibayasuhiro.com/Publications_files/Iba_et_al_2009.pdf

Are rudist the only bivalves with an "elevator" strategy?

No,there was also Lithiotis,a fairly typical Tethyan bivalve,which was pretty elongated.

http://www.bioone.org/doi/abs/10.1669/0883-1351(2004)019<0051%3ADLBIFT>2.0.CO%3B2

http://www2.muse.it/pubblicazioni/6/actaG81/02acta%20g%20posenato.pdf

Edited June 9, 2016 by doushantuo

[DPS Ammonite]

To go with prior post.

You have two other fossils on the Durania. In the post #2 photo, the small encrusting oyster visible in the upper part of the photo is Pseudoperna congesta. See: http://www.thefossilforum.com/index.php?/topic/58968-texas-north-sulphur-river-lagerstaette/ The small tear drop shaped holes in the shell visible in the upper left of the photo are burrows, Rogerella, make by acrothoracican barnacles. See my photo of Rogerella on a Pennsylvanian Spiriferella texanus from Jacksboro, Texas.

Edited June 9, 2016 by DPS Ammonite

[Guguita2104]

I agree with rudist and encrusting oysters.

Regards,

[abyssunder]

Rudist for sure, also Durania is a good match. http://www.thefossilforum.com/index.php?/topic/63506-any-ideas-what-this-is-found-in-a-creek-bed-near-austin-texas/